In a planetary gear hub assembly for a driven wheel in a vehicle independent suspension system, an input drive shaft is fitted with an articulating joint to enable the hub/wheel assembly to move relative to the axle differential assembly to which it is connected. The angular displacement of the jointed shaft creates axial loading on the planetary hub input drive shaft. In some cases because of space constraints, it is not feasible to fit a thrust bearing on the input end of the planetary sun gear input drive shaft. In such cases an arrangement comprising a thrust pad may be fitted at the sun gear end of the input drive shaft to react the axial thrust arising from the angulation of an input propshaft connected between the axle differential assembly and the input drive shaft. There are difficulties associated with the pre-setting of such arrangements to give and maintain satisfactory end float to the sun gear. An example of a known prior art arrangement of this type is shown in FIG. 1 which shows a prior art planetary gear hub assembly 1 comprising a housing 2, a planetary sun gear 3 rotatably mounted in the housing 2, the planetary sun gear 3 meshing with a set of planet gears 4, said planet gears 4 meshing with a ring gear 5, and a thrust bearing indicated generally by the reference numeral 6 on an end wall of the housing formed by an outer end cover 7 of the housing 2 for engagement by an outer end of the planetary sun gear 3. In this case the thrust bearing 6 comprises a thrust wear pad 8 forming an integral part of an oil-fill screw 9 mounted on the end cover 7. When the correct end float has been established by screwing in the oil-fill screw 9, an inner end of which also acts as the thrust pad 8, the oil-fill screw 9 is fixed in position by means of a locking nut 10. Another prior arrangement is shown in FIG. 2. A disadvantage of these known systems is that the correct adjustment may be lost for example when the oil-fill screw 9 is undone to check the hub oil level.
The present invention is directed towards overcoming these problems.